基于受扰轨迹空间解耦的直驱风电机组非线性动态降阶方法

Nonlinear Dynamic Order Reduction Method of Direct Driven Wind Turbine Based on Disturbed Trajectory Space Decoupling

保留风电机组主导状态变量的动态非线性降阶是分析大规模风电并网系统大干扰稳定的先决条件。为此,该文基于受扰轨迹空间解耦,提出一种适用于风电系统大扰动场景分析并保留状态变量的直驱风电机组模型动态降阶方法。首先,基于轨迹分段线性化方法提取故障后受扰轨迹。以欧氏距离为筛选标准在受扰轨迹上提取线性化点并在每个线性化点处构造局部线性化模型。然后,基于空间解耦分别建立每个局部线性化模型状态变量对主导特征根的广义参与矩阵,进而对直驱风电机组进行多时间尺度划分,并以此为基础,利用奇异摄动法建立直驱风电机组的降阶模型。最后,在改进的测试系统中从暂态响应出发对降阶模型与全阶模型的动态特性进行比较。仿真结果表明,依据该文方法建立的降阶模型具有较高的精度、计算效率和稳定性。

Retaining the dynamic nonlinear reduction of the dominant state variables of wind turbines is a prerequisite for the analysis of large-scale disturbance stability of wind power grid-connected systems.Therefore,based on the spatial decoupling of the disturbed trajectory,this paper proposes a dynamic order reduction method for the direct drive permanent magnet synchronous generator(PMSG)that is suitable for the analysis of large disturbance scenarios of the wind power grid-connected systems and retains the state variables.First,the trajectory of large interference disturbed state is extracted based on the trajectory piecewise linearization method,then the linearization points are extracted on the disturbed trajectory with Euclidean distance as the screening standard,and the local linearization model is constructed at each linearization point.Secondly,based on the spatial decoupling,the generalized participation matrix of the state variables of each local linearization model to the dominant eigenvalue is established,then the PMSG is divided into multiple time scales,and the reduced order model of the PMSG is established according to the singular perturbation method.Finally,in the improved test system,the dynamic characteristics of the reduced order model and the full order model are compared from the perspective of transient response.The results show that the reduced order model established according to this method ensures high accuracy,computational efficiency and stability.